Automobile noise has gained interest recently with rising consumer expectations. In the past, engines, transmissions, and tires were of the most concern to researchers, but as these became quieter, and with the advent of electric vehicles, aerodynamic noise became more significant.
A vehicle's side window can be one of its most important sound sources. This happens because the A-pillar vortex makes the glass vibrate and radiate sound into the interior.
The article by J. R. Callister and A. R. George entitled "The Transmittion of Aerodynamically-Generated Noise Through Panels in Automobiles", Second International Congress on Recent Developments in Air- and Structure-Borne Sound and Vibration, March 1992, Auburn University, discloses a simplified model of an automobile side window which was subjected to wind tunnel tests. The transmitted noise level was predicted with a Statistical Energy Analysis (SEA) model, which used a single empirical expression for the fluctuating pressure on the automobile side window. The analytical prediction method predicted the frequency distribution of transmitted noise.
The U.S. Pat. No. 4,553,354, to Barbero, recognizes the noise created by automobile window vibration.
The U.S. Pat. No. 4,571,886, to Shiraishi, also discloses automobile window vibration and its attendant noise.
The U.S. Pat. No. 3,904,456, to Schwartz, reduces noise by an air space and a plastic film. The experiment established that sound reduction was related to calculations based on Berger's Law.
The U.S. Pat. No. 3,875,706, to Okawa, discloses that the transmission of sound through a window is effected by the glass supporting material and the thickness and spacing of the glass sheets.
The U.S. Pat. No. 5,097,512, to Batey, discloses the concept of simulating an acoustic test condition by actuating a plurality of transducers printed on detector film which is located adjacent a test block. The output of the detector film is inputted to test equipment via a PCB, thereby avoiding testing the block in water.